(FORTUNE Small Business) – This time last year it seemed that everyone was becoming an entrepreneur, going to work for one, or apologizing for not being one. Not since Ronald Reagan's dewy-eyed tributes to entrepreneurship had the idea seemed so chock full of goodness, and the youngsters running off to start dot-coms cloaked themselves in entrepreneurial terms like "risk-taking." Problem was, most of them weren't entrepreneurs. Or so I'd argue.

Some 200 years ago the French economist Jean-Baptiste Say coined the term "entrepreneur" from the verb entreprendre, "to undertake." The word has always eluded precise definition, but a colleague of mine once came pretty close when he wrote: "An entrepreneur is someone who takes nothing for granted, assumes change is possible, and follows through; someone incapable of confronting reality without thinking about ways to improve it; and for whom action is a natural consequence of thought." A man is walking down the street and falls down a manhole, and he starts a company devoted to manhole safety: That's entrepreneurship.

The hordes who launched businesses at the height of dot-com mania, on the other hand, were what I'd call "opportuneurs"--people who started companies for reasons that were fundamentally opportunistic, not creative. A man walks down the street, falls down a manhole, and starts a class-action lawsuit to sue the city for $10 million: that's opportuneurship.

Telling the two apart has been no easy task in recent years, in part because opportuneurs did such a fine job of co-opting the vocabulary and attitudes of entrepreneurs--not to mention their casual wear. But confusing the two is like mistaking a day-trader for Warren Buffett.

Consider the story of an old college roommate of mine, whom I'll call Robert. To my knowledge, Robert had never betrayed any independent urge to start a company. On the contrary, he had opted for the bluest of blue-chip paths: a stint at McKinsey (the most prestigious consulting firm), a stint as a venture capitalist (the prestigious profession of the moment), and a stint in medical school (because doctors are eternally prestigious in that time-less sort of way). Then, in 1999, he left medical school to co-found a dot-com.

Had Robert suddenly discovered his long-repressed inner entrepreneur? Had he learned that, deep down, he had a genetic compulsion to create? Perhaps. More likely, he had noticed that the capital markets were bestowing free money--millions of dollars' worth--on people just like him.

There's nothing quite so harmful to an opportuneur's sense of well-being than to watch less-deserving people get rich. And, especially on the nation's business school campuses, this realization set off a frenzy that was basically indistinguishable from panic. "There was just this sense of, If you're not an entrepreneur, you're nobody," says Phil Buchanan, a management consultant in Boston who graduated from Harvard Business School in 2000. That same year, like a giant school of fish, 500 of his classmates headed to Silicon Valley on a job-hunting trip called WesTrek. "These kids were running for the doors," says Randy Komisar, a Valley entrepreneur and an investor who often speaks at business schools.

There's nothing wrong, of course, with taking advantage of an opportunity. And to be fair, many of these opportuneurs possessed brains, a genuine sense of excitement, and certainly no shortage of bravado. Morally corrupt they were not.

Yet by insisting they were entrepreneurs, they corrupted the concept of entrepreneurship.

Risk? What risk? Take, for instance, the notion of risk. At the bubble's peak, MBAs congratulated themselves for daring to join the e-business revolution and become "risk-takers." But let's get real: They were willing to become "risk-takers" just so long as there wasn't much risk involved. And there wasn't much, really. Instead of mortgaging their homes and hitting up their families for money--financing techniques of the traditional entrepreneur--opportuneurs could play with the money of strangers. Screw things up, and they didn't lose their homes; they got their options repriced. "When people come to the Valley, the risk they're taking is, instead of making $150,000 a year on Wall Street, they agree to take $75,000 a year for a shot at a billion," Komisar told me in January 2000. "How is that risk?" One Valley CEO put it even more bluntly: "Risk, my ass," he said. "These people want all of the reward with none of the actual risk."

No parachutes: Career risk had abated, too, thanks to the safety of the numbers involved and the concept of "failing forward." Says Sam Hill, a Chicago consultant and occasional FSB contributor who works with company owners: "A huge number of these people either had or thought they had a parachute in their briefcase."

The fact is, for all their talk of individual "risk-taking," for all their pretensions of "revolution" (and at their most ridiculous, Buchanan notes, students "spoke of the whole e-business phenomenon as if it were some kind of critically important social movement"), the opportuneurs were an essentially conservative lot--resume polishers in revolutionaries' clothes. What had once been a truly subversive, oddball act had become an orthodoxy of its own. "I really think it was like kid's dress-up," says Hill. "People found a box of old entrepreneur clothes and tried them on in front of the mirror."

Return of the company-builder: Now that the market is no longer nodding and smiling at their antics, the game isn't much fun anymore. And so the unmasking begins: Who were the opportuneurs, and who were the entrepreneurs? The latter, as a rule of thumb, will not be seen retreating to the safety of banking and consulting. "It doesn't matter if it's good times or bad times, if you're an entrepreneur you have no choice--you're just afflicted, you can't get over it; it's just a disease," says Jim Collins, who taught entrepreneurship at Stanford University while co-authoring the highly regarded book Built to Last.

For these constitutionally unemploy-able types, those who would be starting companies no matter what the economic conditions, the market pullback should come as a relief--a chance to focus on building an organization instead of satisfying the demands of the capital markets. "In an ironic way, it's really an enjoyable period for me and the company," says Justin Kitch, founder of the Website-building company Homestead.com and longtime critic of dot-com opportunism. "We're going back to bootstrapping."

That's a word we haven't heard in a while (it means growing a business when you don't have any money), and it's one that opportuneurs aren't likely to enjoy the sound of very much. "Do you scuba dive?" asks consultant Hill, trying on another metaphor. "When you get in the pool during the first class, some people see the water close over their head, they get out of the pool, and they never come back. That's what we're seeing now. People tried being entrepreneurs for six months, one inch of water closed over their heads, and they're running back to IBM."

Some commentators have interpreted this flight as the end of an entrepreneurial era. "Entrepreneur's 'Golden Age' is Fading," the New York Times declared on its front page a few months back. But such pronouncements tend to miss the point. In 1989, following the downfall of many of Wall Street's so-called "paper entrepreneurs," the Washington Post warned that "there are signals now, however faint, that the Cult of the Entrepreneur may have run its course." In fact, America was then on the cusp of its most entrepreneurial decade ever. And there's certainly no reason to think a similar future isn't in store today.

What is ending is the golden age of the opportuneur--a period when wealth became decoupled from contribution, risk- takers were replaced by risk-fakers, and exploiting external opportunity became more important than pursuing inner vision. We should hardly lament its passing. A recession, one saying has it, is a time when money is returned to its rightful owners. Perhaps this slowdown will return, as it should, the title "entrepreneur" to its rightful holders.